Hi all,

I was looking through my GE8 manual last night and I read a section where it was written at which speed you should shift to save fuel...I don't have the manual with me so I can't give you any numbers right now.

I've been owning cars for only 5 years, so I'm still learning. However, I was under the impression, and quite possible wrong, that the sooner you can shift, the less fuel you will consume because the RPM stays low. I usually shift when the RPM is between 2000 and 2500, thinking I'm saving fuel because I shift at low RPM. Looking at the manual, it looks like that the speed mentionned for each shift are reached at much higher RPM than 2000-2500.

So my question is...am I right or wrong to shift at low RPM ? Should I follow the manual ? Keep in mind that it is to save fuel; not for racing/fun. And shifting at low RPM, can it cause any issues on the hardware (transmission, engine...) ?

Thanks !

Neo.

 

I have always followed pretty close to what the owners manual says or i look at the speedometer and shift at 15 mph to 2nd, 25 mph to 3rd, 35 to 40 mph to 4th, and 50 into 5th. I've averaged about 34mpg's over 30,000 miles on this car. Shifting at such low rpm's actually uses more gas cause you're lugging the engine. Your Fit's engine is meant to rev a little higher. The old rule of thumb was always to shift at 3000 rpms which is pretty close to what the owners manual is telling you, maybe slightly higher. Plus the car will be much more zippy for you. Give it a try, you'll still be just fine on your mpg's.

 

And lugging (shifting to soon or driving to slow in a higher gear) your engine is actually worse for your engine than running it at slightly higher rpm's.

 

May I ask why ? I'm no mechanics, sorry for asking...

 

I am not a mechanic either but I have done research on this. Basically from what I've read is that when shifting way to soon, the fuel doesn't burn at an efficient rate but rather explodes at the wrong time. This causes wear on the cylinder walls and eventually leads to you needing a new engine much sooner than you normally would. I would trust what your owners manual tells you because you will hear varying opinions on this. I think Honda know their engines best and obviously wants their products to maintain reliability for their reputations sake. Try following the owners manual recomendation for your next tank of gas and measure how your fuel economy was.

 

I shift at 3k rpm. 95% of the time.

I've found it gets me about 40 mpg.

Although, the other 5% of the time I'm shifting at 6300ish.

 

I think 3k to 3.5k rpm is a good rule of thumb for a balance between efficiency and power. And of course you gotta push this amazing little engine once in awhile lol!

 

Whoa. Oshkosh!?

 

Ahhhh, I didn't even realize you're a fellow Wisconsinite! Yaderhey lol!!

 

Shift before 4k, don't worry as much about the accel fuel usage as much as you do about the fuel you use while cruising. There's much more to be saved at steady cruising speeds and slowing to stoplights than there is for the .1 miles in which you're speeding up. Don't jam on the accelerator, maybe 1/2 throttle, smooth inputs on accel.

I get between 38 and 40 mpg mixed city/hwy (with San Fran freeway traffic). Idling in gear is your friend, avoid the brakes at all costs.

 

Thank you everyone for your answers and the explanation on lugging. I began yesterday to shift higher than I'm used to (between 3K and 4K). I do a lot of milage and I did not notice an increase in my MPG, but one day is not enough to confirm that.

And, as some of you said, the engine is fun to drive so lets drive it properly

 

If it's really level does it lug the engine that much? It seems like when I shift at 2k on a flat level road, and really easy on the throttle it seems fine. Maybe I need to watch it more...

 

I've been experimenting with the shift point as well and found that if on a level road and taking it easy shifting at 2k can be smoother and don't notice any engine lug.

However a greater percentage of my driving is more spirited, shifting between 3-4K or higher. As stated it's just more fun and zippier without any noticeable mpg degradation. I actually saw a mpg improvement on a recent trip through windy, hilly mountains using higher rpm shift points

 

This is when it really pays to hold your gear, up mountains and grades. Less throttle, more rpm. I'm glad your experiments are giving gains.

 

Obvious thing---just pop it out of gear and coast down hills.

 

Maybe in WI, unlawful in CA. Dangerous on the mountain roads around here. I do coast up to stop signs or red lights on level ground.

 

Not so obvious, but if you pop it out of gear, the car has to use some gas to keep it from stalling. Better yet, shift to a higher gear and coast down hills, taking advantage of the Deceleration Fuel Cut-Off (DFCO) that happens above 1500 RPM. Or, if you are feeling adventurous, put it in neutral and shut off the engine (legality aside). From a safety standpoint, the Fit has electronic power steering, which will kick back in after a few seconds once you turn the ignition back on, and the vacuum in the brake reservoir has about 3 or 4 seconds of hard braking before it runs out. On a good day, and with luck at stoplights, I can coast halfway to work (that doesn't work on the way home).

Above all, be safe. Lawsuits and car repairs are much more expensive than any mileage gains we can make in cars which are already so efficient.
--
Barry, '08 BBP Fit Sport MT
(who lives about 1000' higher elevation than where he works)

 

I have driven up to Running Springs. I agree that it is dangerous to pop it neutral on that hill! Better to coast in gear.
--
Barry

 

Reving too high (especially with no load) wears out the rod bearings.

Lugging the engine (too much load, not enough revs) wears out the main bearings.

A nice balance keeps both bearings happy.

 

hey I'm from oshkosh too. Currently living in GB though.

Anyway. I didnt read the whole thread. But you have to remember that RPM does not dictate fuel consumption. For the most part, throttle position does. And the lower the RPM you shift, the more throttle its going to take to pull you back up into a rev range where you actually have enough torque to accelerate.

General rule of thumb when accelerating/shifting is that you want to keep the engine in its torque band so that you can use less throttle and still be able to accelerate to the speed limit.

Like say you leave a stop sign in first, and shift to second at 2000rpm. That will put you at like 1000-1500rpm after the shift... which is barely above idle. Now you have to mash the gas to try to get back up to 2000-2500 to shift again, which uses more gas than if you'd just shift at 3k-3.5k where you dont have to apply as much throttle.